1. Field of the Invention
The present invention relates to a color conversion device.
2. Description of Related Art
Conventionally, a color printer is provided with four cartridges that store inks of colors of cyan (C), magenta (M), yellow (Y), and black (K), respectively. In order to form a multi-color image on a recording paper, the color printer forms images of the respective colors of C, M, Y, and M and by superimposing the four single-color images on top of one another.
The color printer receives a CMYK color value set (C, M, Y, K), which is constituted by cyan, magenta, yellow, and black control signals C, M, Y, K. Each control signal has a value representative of 256 gradations from 0 to 255 for a corresponding color. For example, a CMYK color value set (0, 0, 100, 0) indicates light yellow, while another CMYK color value set of (0, 0, 200, 0) indicates thick or dark yellow. The color printer reproduces multiple tones for each color by adjusting the amount of the corresponding ink according to the CMYK color value set (C, M, Y, K).
Incidentally, coloring degrees of inks used in different color printers are different from one another. Accordingly, even if the same color value set (C, M, Y, K) is used in two different devices A1 and A2, colors reproduced by the devices A1 and A2 will be different from each other. Therefore, when device A1 is controlled by some color value set (C1, M1, Y1, K1) to produce some image and when it is intended to control the device A2 to form the same image, a color conversion device has to convert the color value set (C1, M1, Y1, K1) into another color value set (C2, M2, Y2, K2) that can control the device A2 to reproduce the same image.
In order to convert the color value set (C1, M1, Y1, K1) into the color value set (C2, M2, Y2, K2), according to an ICC (International Color Consortium) color management, the color conversion device first converts the color value set (C1, M1, Y1, K1) into a standard color value set (L, a, b) or (X, Y, Z) by using an ICC profile for the device A1. The standard color value set (L, a, b) or (X, Y, Z) is defined by the CIE (Commission Internationale de l'Eclairage). The color conversion device then converts the standard color value set (L, a, b) or (X, Y, Z) into the color value set (C2, M2, Y2, K2) by using another ICC profile that is for the device A2. Each ICC profile includes data indicative of a correspondence between a plurality of representative color value sets (C, M, Y, K) used in the corresponding device and a plurality of representative standard color value sets (L, a, b) or (X, Y, Z). Each ICC profile is prepared in a file format that is set by the ICC.